Cold Damage on the Acacia Willow

Identification

• Acacia willows are often used in residential plantings, as specimen trees and planted in groups. Native to Australia, these trees have narrow green or gray leaves, fruit pods that measure 3 to 4 inches in length and creamy-yellow or white, fragrant flowers that bloom in late summer. Acacia willows are cold hardy to 20 degrees Fahrenheit. Trees growing in some areas survive temperatures in the mid- to high teens.

Effects

• Willow trees suffering cold weather damage may develop black or brown foliage in new shoots and flower buds. These trees are most susceptible to injury from cold temperatures in the early spring, when the trees are actively growing. Patches of frost may affect lower portions of the trees. Evergreens damaged by frost also develop downward curling of shoot tips that turn brown shortly thereafter. Sunscald is also a problem on cold winter days and is often seen on willows, as they are thin-barked trees. Newly planted willow trees are most susceptible to sunscald. Willows suffering from sunscald often develop red or orange bark that cracks or becomes soft.

Prevention

• There is no cure for cold damage. Preventing cold injury is the best way to reduce damage during the winter months. Plant acacia willow in climates where it is adapted. Avoid planting it in very low-lying areas susceptible to frost. Water the tree thoroughly in the fall, preparing it for the coming cold weather. Wrapping the trunk avoids sunscald. Place the wrap on your tree in the early fall and remove it in late April for maximum protection.

Considerations

• Keeping your acacia willow healthy and free from drought stress avoids cold injuries during the winter months. Cold weather injuries occur when temperatures change quickly, and when trees are drought stressed. Winter injury increases the likelihood of boring insect infestations or canker diseases.